Conventionally, in a projection display device (hereinafter referred to as “projector”), e.g. a liquid crystal projector, light modulated by a light modulation element, e.g. a liquid crystal panel, is projected onto a projection surface by a projection lens. Examples of the light source include a lamp. When a lamp is used for an extended period of time, the lamp deteriorates. Thus, after having reached its end of life, the lamp needs to be replaced with a new one.
In order for the lamp to be replaced smoothly, a projector main body can include an aperture through which the lamp is taken in and out. In this case, the aperture is covered with a cover. When replacing the lamp, the user opens the cover and takes out the lamp.
A detection switch for detecting opening and closing of the cover can be disposed in such a projector (see Patent Literature 1, for example). When the user opens the cover while the lamp is lit, the detection switch detects that the cover is opened and the lamp is turned off.
In order to increase the intensity, such a projector can be configured so as to include a plurality of lamps, which is called a multi-lamp configuration. In this case, each lamp has an aperture and a cover. A detection switch is disposed for each lamp.